Could this be the sign of HDD crash?
Long story short... My dad brought me an old computer (hp xe783, Intel Celeron, Windows Millennium Edition) to work on (remove viruses, old programs, and whatnot) for my younger sisters to use. I switched from the OEM pc100 64GB RAM stick to two pc133 256GB RAM sticks. After a THOROUGH INTERNAL cleaning of the case and hardware, I started it up and began the virus scans. I think I ran the Avast! Scan three times (once initially, once after removing several old programs and other junk, and once again after some more fine tuning). I even ran defrag a time or two. After all of this was said and done, I tested several Windows programs, control panel, and Internet Explorer... everything worked. It was actually a hell of a lot faster than the first time I booted it up. Here's my problem: after all of this, I shut it down completely, unplugged all peripherals and power cords, and cleaned it (keyboard, cords, monitor). When I rebooted, it shows the HP splash screen and then goes to a black screen for a second, and says "no operating system found". What's that all about? I didn't disconnect anything inside the case. I waited several hours for it to dry after cleaning it. What do I do now? If I need to reinstall the OS, could someone give me a link to show me the process? Thanks.