First of all, thank you for your help. I have passed through all the steps described (erunt,tfl,rooter,locksearch,cks,Gmer and otl). Finally I did a system restore by means of "%systemroot%\system32\restore\rstrui.exe). I don?t know if it worked or not... during all the scans several virus were found and deleted but once neither after all the scans nor after the last restoration has changed anything in the computer. The icons, the windows start and the bottom bar are gone. I can only see my wallpaper and I need to open everything by means of Ctrl+Shifth+Delete. I have to download all the software to a USB memory, open it by means of Ctrl+Shifth+Delete and so on... I kept severeal txt files with the results of the scans but I cannot copy them to the stick. Besides, I can?t access to internet since the computer corrupted although I can see, exploring by means of firefox, that my files still are in my C:\.
Sincerely, I don?t know what else could I do. Would it be possible to simply erase every single file or data created during the last 48h?
*My operating system is windows XP Home Edition bought in late 2005 in Spain.
Thank you for all your help.