lots of strange problems with computer

hi,

i have windows 7 64-bit. a while ago i had some malware on my system, which was cleaned. however this happened again fairly recently and as far as i know now, the system is cleam again.

ever since the first instance though windows took alot longer to load. the display swiched between windows 7s basic theme and the usual premium theme (i have win 7 premium). the nework service wouldnt start properly while it was doing this but eventually it was ok.

now the hard drive hangs alot. when downloading i always get i/o errors, everything freezes etc. and even though i have antivirus/firewall on it says my antivirus is turned off and windows firewall is turned off even though im using a different firewall. :confused