Need some help

I have a XP SP3 Pc with some deep problems.
1. Cannot update Winxp with the update function. ( error 8007002 )
2. When I put a USB key memory the drive is recognized but not accessible
3 When I run the disk management I have no drives, and running PM8 I get the 117 error.
I made a scan with Norton 2009 and with the confiker tools and windows live one care without success.
What can I do ?
Could be a Malware ?
Regards

 

I wish to thank the forum for the support.
I read some sticky and with combofix I solved completely my problems.
Many thanks to the moderators.
LT99