|"Now, the worst part... I thought the problem was in my G15 keyboard (connected via USB), and I connected my old Logitech Deluxe Keyboard via PS/2 port, and the problems are the same. I`m using Windows XP SP2."|
If you had not mentioned that, I would have suggested the following as the most likely thing, but I will mention it anyway, because it COULD apply to both to BOTH keyboards - if you have another keyboard aswell you can try, try that too.
Apparently your G15 is a corded keyboard, and I'm assumimg your PS/2 connected one is too.
It is very common for wires to get broken inside the cable for a keyboard (or a mouse) after it has been used a lot, or if the cord has EVER been yanked on, or if it was frequently unplugged by pulling on the cord rather than the connector on the end of the cord. Often the wires are broken inside the cable right where it enters the keyboard (or the mouse) - if you re-position or wiggle the cord there, or next to the connector that plugs into your computer, you MAY see the weird symptoms will come and go. If the broken wire ends are still touching each other within the intact insulation of the wire, the device still works but the connection of that wire is intermittant rather than being reliable, so sometimes the device will behave weirdly - sometimes it's as if some malware is controlling it.
If you DO have that problem, the keyboard will NOT work properly connected to ANY computer, at least some of the time.
There is no cure for that, other than you chopping off the cord before where the wires are broken and re-wiring it to the keyboard (or mouse) inside the device, or re-wiring it at the other end of the cord, and even then the keyboard circuits may already be damaged.
or you use a properly working keyboard.
Try BOTH keyboards connected to another computer - you may need to install software for the G15 BEFORE you first plug it in.
If they BOTH work fine connected to another computer, your computer mboard is probably damaged and you need to replace it!
Try yet another keyboard with your computer if you can.
How could it have gotten damaged?
- a power spike or surge, often experienced during a power failure event
- a nearby lightning strike, or a nearby lightning strike on your AC power grid
- a static electricity discharge - DO NOT use a vaccuum cleaner to clean your computer - they produce a tremendous amount of static electricity! - if the computer is in a location with synthetic carpet and low relative humidity, it could have gotten a discharge from that source
- for a desktop computer, damaged caused during the failure of a computer power supply that you have since replaced, or by a ps presently in the process of failing
Failing power supplies are common and can cause your symptoms.
Check your PS.
See response 4 in this: