Thanks coman_nick for your reply.
I've just done all that and still cant install the App2sd..
Ok, here is what I've done in detail, hopefully u can find the fault in my process..
1. connect my hp to my PC.
2. copied all 4 files provided by Mr Suhel into my SD card, (app2sd.sh - 4kB), (busybox - 1804kB), (sh.sh - 1kB), (mount_sd.sh - 1kB). There is a busybox file in it so it was replaced.
3. switch on my USB debugger.
4. safely remove my SD card but by hp is still connected to my PC, SD card is also unmounted in my X8.
4. Open DOS cmd.
5. at C:\>, i typed 'cd adb' (meaning in my C drive there is already a folder named 'adb' with the 3 files from SuperOneClick; adb (564kB), AdbWinApi.dll (94kB), AdbWinUsbApi.dll (60kB))
6. then i typed 'adb shell', a $ sign came out.
7. then i typed 'su', my hp shows 'Unknown has been granted Superuser permissions', a # sign came out.
8. then i typed 'sh /sdcard/app2sd.sh', enter and they gave me 'Can't open /sdcard/app2sd.sh'.
Can u tell what is wrong from here?
Thanks.