Right, thanks to lots of people here, AVG, jeremy wilkes and sgtbadgerman i have finally figured it all out...
The Signs
There are three main things to look for if you think you may have the virus.
1) Limewire constantly keeps opening, and if you un-install it it still tries (and comes up with an error
2) Ctrl-Alt-Delete will not work. This is so the virus is not seen eatingall the cpu
3) In c/Documents and Settings/main user there will be a folder called complete or uploads or something of the sort. Its a hidden file, so make sure you have hidden files on and system filen on aswell. In complete will be a load of zip files, usually with porn names. DO NOT BE FOOLED! Each one is the virus, and each folder is uploaded to limewire, so more people get it. This is why limewire keeps opening!
The Virus
****** this thing is smart! It cannot be detected by any antivirus (that i know of) and can take over programs. (it took over my previous antivirus!!

) It also takes up all your CPU, so if your comp is running slowly, check the signs. Its also extremely good at hiding

.
How to get rid of the bugger!
Right, this is the hard part.
1) Check all the signs
2) If you know you have the virus, uninstall limewire, this is the first place it hides.
3) Delete .limewire This is in c/Documants and Settings/Main User
4) Do a file find for limewire, delete everything.
5) Now limewire has gone, you can start getting rid of the virus. First, see if you can get into task manager a different way. Sometimes you can, sometimes you can't. To see, go to c/windows/system 32/taskman.exe If you cant open task manager this way, it will probably come up witht eh program is in use. You will need to make a shortcut to task manager on your desktop, re-start your PC and click it straight away.
6) If you can get into task manager, go to processes and double click CPU. Something will be using close to 100%. Write down what it is. It is most likely to be ms movies or winupdates. again, DO NOT BE FOOLED! This is the virus hiding under a windows program!. If the virus is not one of the two, do a file find for what it is. DELETE EVERYTHING that is suspicious. It may have taken over some programs (it did with my antivirus, i had to delete it)
7) Now, if you did or didnt find what the virus is named, turn your computer off and run it in safe mode. (push f8 at startup and select safe mode). If you get the option to cancel loading something using esc, do so. Booting in safe mode may take a while...
8) Go to c/program files and look for winupdates, or ms movies. It'll be hidden. If not, look for what you found in taskmanager. Delete this file, then go and delete complete or uploads. re-start the PC and check the signs. If none appear,

. However, if they do appear, i'm afraid i cant help....
I hope that this helps. If you have had the virus for a while, it may be slightly harder to get rid of the whole virus. Just keep looking through your system. Filefind is a wonderful tool
GOOD LUCK
FuriousPanda