windows cannot access specified device,path or file error on D clicking c drive

win xp
hey..
noob here. i have been going through a string of problems with my C: drive. on double clicking it used to open the "open with" dialog box..then i used a-squared scan which detected some malware which i removed. it now gives me the " windows cant acces device error..the folders in C: open when i use "Run".. the address bar in the explorer window has disappeared even though its enabled. cant figure out this one...could someone help please

thanks a ton