c drive help?, nothing workin

Hi, i was wondering if anyone could help me

Im on windows xp home.

Well, nothing seems to be workin, it wont defrag, it wont do a disk check , nothin will load up exept from firefox and a few other things, i cant install anything, i cant even click on c drive it says access denied or i get the error message 'Windows cannot find 'recycler/s-2-9-50-1000029363-100026996-4265.com. make sure you typed the name correctly and then try again'. I have tried everything i can think of but i cant run any of my virus or spyware software etc, it did allow me to run antivir xp but it didnt help, i also tried to do a system resore but it wont allow this either , i click next and nothing happens.

Also on startup i get the error missing boot.ini file booting from c:/windows. Do you think this could be anything to do with it? i have instruction on how to fix that but do not have an xp disc , the pc has recently had a new hard drive and it was like that when i got it back but everything was workin fine
untill today.

Any ideas anyone? be greatly appreciated

Ive now been told it is probably malware, but its blocking my applications from working so how can i remove it?

Have you tried booting into safe mode? Tap the F8 key while the computer is booting, select Safe mode with networking (That should allow you to get online) then go here:

ewido - anti-spyware and anti-malware solutions

Click the "Scan now" button on the left of the page. Report back after the scan.

another decent one i use is malwarebytes

If you're still stuck then ask somebody to download DrCureit on to a flash drive. You can then run the .exe file from the usb flash drive. It will scan your hdd and clear the malware enough so you can scan with your AV and other spyware scanners to clear up completely.
Download Dr.Web CureIt! Free anti-virus scanner, cures computers viruses.