Welcome to the forum.
It appears that your CPU does not support the SSE2 instruction set. Do you have an older AMD?
Unfortunately, the only "fix" is to buy a computer with an updated CPU - one that does support the SSE2 instruction set, or find an older version of PrE and PSE, before SSE2 became part of the necessary specs.. Not sure if PrE 3 required SSE2, but others with a better grasp of history should be able to tell you.
Good luck, and sorry for the bad news,
Sorry you've lost me whats a CPU and a AMD? I have operating system windows xp but have another tower which is windows 7, should i install it on to this one?
It should install on that Windows 7 machine without too many problems. (Although version 9 is a much more stable version of the program.)
It's very likely your XP machine is running a processor that's too old to run the program. You can find out by right-clicking on My Computer and selecting Properties. If you've got an old AMD processor listed, that would explain the problem you're having.
CPU = Central Processing Unit, or the silicon chip that does the computations
AMD = Advanced Micro Devices, a maker of computer chips, and especially CPU chips. They were a bit late to the SSE2 instruction set, and many users of their older CPU chips had to upgrade to the newest AMD CPU's (most often meant a new MoBo - motherboard too). Intel implemented SSE2 instruction sets earlier, so fewer Intel users were impacted.
From the Adobe Premiere Elements 8 Minimum System Requirements:
2GHz or faster processor with SSE2 support; 3GHz processor required for HDV or Blu‐ray; dual-core processor required for AVCHD
Much the same happened, when Adobe rewrote the code for Premiere Pro CS 5, so that it would only run on a 64-bit OS (Operating System). Many still had 32-bit OS's, and had to upgrade the system, and often with both the OS software, and the hardware to run it.
I would also anticipate that the Win7 machine has a newer, SSE2-compliant CPU, and that PrE 8 should install on it.
I would immediately update PrE 8, as the patch fixed some GPU (Graphics Processing Unit - the chip on your video card) errors. What was the official name of that patch, 8.0.1?
It is good that the OP has a second, more modern machine.