I have a emachines 3260 PC which I recently brought an upgrade for the ram which turned out to be different to the installed ram when I spoke to the company I got it from they suggested just replacing the installed ram I did this and when I powered up the computer it beeped 3 times and no picture appeared on the monitor screen, so I replaced the old original ram , and upon start up did the same series of beeps so I tried replacing it again now the machine won't boot just makes a skipping sound when it is supposed to make the single boot beep ? Now I seem to recall that there is a way of rebooting by pressing something inside the computer which bypasses the reboot programme am I right in this ?

You can reset the cmos to default inside the PC if you can find the cmos reset jumper (some new PC's have a button) Or you can remove the motherboards button battery for a minute or two to do the same thing. What was the difference between the new and old memory? Are you using the correct slots? Some mobo's want you to put pairs next to one another and others skip one for better cooling when two sticks are in a four slot configuration. They're usually color coded.

Is the monitor not responding? If the monitor won't work with any new... well,. anything then you need to take that monitor back for a new one and maybe try a different brand. Some brands are prone for first use mishaps like this and if not taken care of right away, they may be un-fixable so id try a more durable brand like Samsung or maybe Dell?

Before you removed the 'old' memory (ram) did you unplug the power cord? It's always a good idea to remove power to the computer before unplugging or removing hardware from the board.

Also, did you make sure the new memory was installed in the correct direction; they have a notch in them to locate them in the correct direction but it can still be put in wrong which could cause some issues. I had someone do that; two sticks of ram from the same manufacturer had their stickers on opposite sides causing them to install both in the same direction(sticker facing the same way) but one stick was installed in the wrong direction.

I would try and reset the cmos then retry the original ram first.

Also, what's the difference between the old ram and the new ram? How much different are they to "not" be able to install them together?

There could be so many reasons behind it such as collection of unnecessary junk files
And invalid registry entries. So you can get rid of this problem by installing Optimo Pro software. It is efficient in solving all your problems and you can also call Click4support at their toll free number 1-877-836-8352