overwing,
spooky, but I think and hope no virus.
Suggest you check your IE Temporary Files settings as follows:
Tools/Internet Options/General/Temporary Files-settings/
Check the Temporary Internet Files Setting (Its hard to see 'cos its in small black font on grey and doesn't leap off the page.
You may find it is looking for the a: drive. If it isn't something like C
Temporary Internet Files\, then click on Move Folder and make the destination a suitable folder on your hard disk.
Come back if that doesn't fix it.
Cheers, fob