Is there a way to set my computer up so i can have a newer operating system like windows 10, 8 or 7, but still use the older monitor from the 90s, early 2000s?

It depends on how old your PC is ! You can go to Microsoft and see if your unit is compatible for Windows 10. If it passes OK, the monitor shouldn't matter. Just depends on if your present PC can be upgraded to 10. Easy to find out. You don't want 8 or 8.1 and 7 will cost you about $100.00. But 10 is a free upgrade for now. Check out Microsoft's webpage for Windows 10.