I installed the modem on my friend's Pentium II IBM PL 300. He also had me check out what he thought was a Pentium 4 I doubt it is more than a Pentium 1 in fact. It would not even boot up. He also had a tall tower case we looked at. The hard drive was connected to the wrong position on the cable but even with it connected to the right position it had no OS. A Win95 install by floppy failed. The tower case had a pentium 133 Mhz in it but we could not access the bios due to a password. As such the case is nice but it needs a new motherboard and perhaps a new hard drive. It looked like it had a 3.5 GB hard drive a Quantum.