I have a Mac Performa 6400/200, but my printer is not working, I wat to buy a new printer but all the new ones required a System 8.0 or up, but my Mac has 7.5. How can I upgraded it? Thanks

Just buy OS 8.6 or above and install to upgrade your system. You can find it cheap on ebay.com.

What you'll probably run into is the lack of any printers that will plug into your serial ports. In addition to upgrading to 8.6 or higher (as Bob said), you'll probably also want to get a USB PCI card. A decent one should be $10-20 (check pricewatch.com, deal-mac.com, macprice.com) and will involve opening your Mac, but it's not *that* hard to install. OS 8.6 is rather RAM-hungry, especially compared to 7.x. If you don't have at least 64MB RAM in your system right now, get two 64MB 5.0V EDO 168-pin DIMMs from your favourite RAM vendor on ramseeker.com and call it good. The 6400 can't take any more RAM than that, but having 136MB will make things SO much easier for you. With a USB card, a nice fat chunk of RAM, and OS 8.6 or higher, you'll be all set. p