First thing would be to go to add / remove programs and remove any bloatware that came with the PC, things like HP solution center or AOL. Software programs that aren't used - ask her what she does and doesn't use.
Second would be to do a virus scan, hopefully she has an up-to-date virus scanner. If not Microsoft Security Essentials is a good one, Avast! as well as AVG are all free and good. Do a full system scann.
Third do a malware scan, I would use malwarebytes, Download the free version from Malwarebytes.org
and install it. Update and scan.
Fifth, if this is Xp run a disk cleanup then a disk defrag. If it is Vista or windows 7 just do the disk cleanup.
Now if the issue persist after that we need more information like the operating system, the laptop type, etc. Need to know more about the hardware before we could continue.