Mariah Carey - The singer's new single 'Triumphant' reached the heady heights of 115 on the US Billboard charts this week, managing to sell fewer units than a bonus track from Beyonce's '4' album last year. Selling just 23,000 downloads is a pretty disappointing showing for someone who has sold tens of millions of albums worldwide, and Carey will be hoping appearances later in the year as a judge on American Idol will help revive her fortunes.

Hyde Park gigs this year have been marred by complaints from attendees about the quality of the sound and early cut-off times. After Blur's show to coincide with the Olympic closing ceremony, many fans took to Twitter to criticise the sound levels in at the gig, while many more were left angry last month after Bruce Springsteen's show at in the park was cut short during a song with Sir Paul McCartney.

Estelle released a new album this year, although you may not have realised as it failed to chart in the UK on its February release. It did fair better in the US, reaching number 28, but it's a far cry from the success of her 2009 album 'Shine', which spawned the massive single 'American Boy' and featured Kanye West.

The Voice was supposed to rival ITV's X-Factor for viewing figures and help the BBC forget about the disastrous Fame Academy show all those years back. Instead, ratings dropped, winner Leanne Mitchell's debut single 'Run to You' failed to make the UK top 40 and the following live tour was cancelled due to poor ticket sales. Yet, despite all this, the BBC still has plans to bring the show back for a second series.

X Factor runner-up Marcus Collins decided, or had decided for him, that covering ''Seven Nation Army'' by the White Stripes was a good idea after the talent show ended. While the single made the UK top 10, the ire directed at his take on the song ensured Collins'' next effort ''Mercy'' could only reach 194. So bad were ''Mercy''''s sales that Collins was forced to reassure his fans on Twitter that he had not been dropped by his label.

Matt Cardle became yet another X-Factor casualty after the 2010 winner was dropped by Columbia in May. His last two singles have missed the UK top 40 by quite a margin, probably not helped by reports in the press that he had suggested the 9/11 attacks "were a conspiracy".

When Tom Cruise is in a film, you can normally bank on a box office success. The exception being when that film, ''Rock of Ages'', is based on a broadway musical set in the 1980s and features Russell Brand singing. It flopped, badly.

Compared to past successes, Madonna''s 12th album MDNA did not quite make the grade commercially or critically. While ''Give Me All Your Luvin'' made the US Top Ten, both her subsequent 2012 singles have failed to chart, and ''MDNA'' itself has the unfortunate record of achieved the largest second-week percentage sales drop for a number-one debuting album in USA.

Viva Brother announced they their split in March after releasing just one album and a string of singles that had failed to chart. The band had previously been NME cover stars and were tipped for the top, but success never really materialised and the band have since resurfaced with a Hurts-aping sound as Lovelife. But whatever happens next, expect the tag of 'former failed britpop copycats Viva Brother' to follow them wherever they go.

Nelly Furtado - Despite her comeback single 'Hoops (Bigger The Better)' being pretty spectacular, Nelly Furtado's 2012 return has been a failure of spectacular proportions. The single failed to chart in the US (it reached No.14 in the UK) and the album, Spirit Indestructible sold less than 7,000 copies in America on its week of release - missing the Billboard Top 50.

Kreayshawn - Formerly tipped as the future of female rap music, Kreayshawn's career seems to have stalled already, with some sources calling sales of her debut album 'the worst first week album sales in music history'. The album sold just 3,900 copies - reportedly the lowest for a major label release ever. "All I can do is pursure my dreams," she said on Twitter.

Tulisa - Landing a guest performer spot on The X Factor is usually a sure-fire way to a chart hit. However, it hasn't seemed help Tulisa at all. Her debut album 'The Female Boss' barely made it into the UK top 40 and at one point only sold 7,000 copies in two days. As if that wasn't bad enough, the former N-Dubz singer has turned the majority of the public against her with rumours of her sex life filling the up the tabloids and foul-mouthed Twitter rants losing her thousands of followers.

Leona Lewis - The Former X Factor winner failed to break into the top 200 with December single 'Lovebird'. On the week of release, the track at No.200 had sold only 600 copies - meaning Leona sold even less. After such success with her earlier albums, it looks as though Leona's run in the spotlight could well be over. At least she lasted a lot longer than most of the other X Factor champions.

Christina Aguilera - The singer attempted to revive her pop career, whilst riding the wave of the Maroon 5 smash hit 'Moves Like Jagger', but failed quite miserably. Lead single 'Your Body' could only peaked at No.34 on the Billboard Top 100 and the album 'Lotus' sold poorly. A good album, but a lack of live performances or coverage meant for a flop of 2012.

Alexandra Burke - Another X Factor winner who has struggled to impress after some initial chart success. New album, 'Heartbreak On Hold' limped into the UK album chart at a disappointing No.18. The record's second single 'Let It Go' also bombed after landing in at No.33, before dropping quickly to No.74. It seems the X Factor winners have a shelf life of about a year or so if they are lucky. Burke blamed her flops on the radio for lack of support after her single 'Let It Go' was pretty much ignored by stations such as BBC Radio 1 and Capital FM.