Have you replaced the coin cell battery? That could be a cheap fix on the old computer. Check your manual for instructions. Support for Studio XPS 9100 | Documentation | Dell US
I have a 11 year old Studio XPS 9100. I have the most trouble with it when I first start it in the morning. Rather than say cold boot, to be more exact, first time boot. It takes several attempts to start the computer, but when it does finally start, it runs fine. I feel that soon, my computer will be completely inoperable unless I do something fast. Please help.
Studio XPS 9100, first boot question