i agree with Headlice. i worked with spyware before and its extremely hard to detect. i've seen key logging software that masks itself as an svhost.exe service and deletes the data bank and creates a new one in a different directory, with different name mimicking system files. there are 2 basic types of spyware software and hardware hack
if it's software spyware i wouldn't junk the computer, just format the suspect computer that should rid the spyware. only after formatting, change all your passwords like windows login, bank account, emails, vpn, etc. this type of software can record information remotely and send through a designated SMTP server back to the person that installed the spyware. and oh yes it will detect anything executed even though it's not installed, so even if you got a CD that can scan, it will record what executable was opened at what time and how long, tipping off the suspect
if it's hardware just junk anything that suspect person gave to you. if this case that usb mouse. with this type of spyware the person usually can't remotely retrieve data because it records right into the unit rather than the computer. there are two popular types both work the same way. plug this into the ps2 or usb port then plug the keyboard into that port. the keyboard must be plugged into directly into this unit for it to capture the key strokes. and even then the person needs to retrieve that key logger unit physically to download data.
here is a similar unit for usb keyboards
http://www.brickhousesecurity.com/home-keystrokelogger-keyphantomusbhome.html
here is a ps2 unit
http://www.keyghost.com/sx/
if the person doesn't have direct contact with this computer i would suspect its software spyware, in this case format, then change all passwords because i would assume the worst that all accounts have been compromised. if he's a electric engineer and he is that sophisticated to create a new hardware hack that can retrieve the information remotely just junk the computer gifts he gave... then format just for good measure... =)