Not Parallels or Windows are corrupted in your case - Parallels Tools installation hanged right? Parallels tools it is actually a branch of drivers - video, network, mouse driver etc. which makes Windows to work smoothly on Mac. As installation proceed to 60% - previous PToos were removed i suppose - this is why your Windows looks so strange. You need to make sure all old files are gone and install tools again from the virtual machine menu--> Install PTools. check this kb http://kb.parallels.com/8969