Pc not booting up, retrieval by network?

Hello, my mom's pc has recently gone belly up, she was having a mooch around the system files and must have accidentally installed or removed something (so I'm pretty sure it's not a hardware fault). Anyway when switched on it shows the usual dos style stuff but it doesn't progress past the windows screen, but then restarts again. I have already tried to do a parallel install but it won't let me install two windows in the partitioned space. Are there any other ways to get at the files without sending it to the repair shop? I have my own pc which runs fine and was networked with this one before, could I use networking to retrieve the files? Please help,

Hannah