Reuse and Recycle old PC parts

Hello everyone,
Let me start with getting straight at the point.

What parts of a complete PC (old and dead) be reused in another one?

Now here is a little description of the PC I am talking about but I would also like general answers that can help everyone.
>I had a P4 system which is about 8years old or older. It died i guess due to a power spike or HDD failure.
Now what are the components that can be reused in such a PC?

I am sure about the few obvious components:
Monitor CRT 17"
CD RW Drive (DVDRW cost a bomb those days)
The Cabinet (considering they have been universal over the years)

Is that all?

I am not looking for any accurate suggestions. I just dont want to throw away something that can still be useful either to me or someone else.

If the reason of failure of the system is HDD failure, you can just buy a 2nd hand hard drive, or if the system can be repaired you can do that. Since Pen 4 still are powerful enough to be made into a Linux or a download machine.

Heck, I have even made run Windows 7 on my Pen 4, which is at least 5 years old, by just increasing the RAM to 1 GB, and by turning majority of the memory hogging processes off. Still using it.

Update: I think it was a spike. Just got to know after a lightening strike the surge killed the mobo. I think most parts are bust.

No chances of resuscitating that old PC.

Have you checked the HDD is another PC? Is it not working?

This happened in my previous home and i was not present while all this happened. It was quickly abandoned and lappy replaced it.

I will have to check if its still viable.

But in case of a power spike which killed my previous HDD too i think the HDD being the most sensitive does get damaged. Also my bro tells me the mobo got burnt. I think that takes the P4 proc and my 256MB AGP gfx card with it.

I just want to know should i just dump the entire PC. Or will i be able to use the case and CDRW to make a download rig?

Check the components in a 2nd PC if possible before dumping. Same goes for optical drive. But the cabby can be reused.

On a different note since i have faced a HDD failure twice due to a power spike despite a UPS (V-Guard duh!) should i get a spike buster for my new PC?''

Will the UPS take care of it otherwise? (APC 1.1KV)

There r many ways u can use ur old Pc

if the monitor is damaged u can use the CPU as a personal Firewall to u Home Net Conection

If The Motherboard,Ram,HDD is Damaged u can get them if it is a P4 u can donate it to some
school or insitutions

U can add an External Drive and us it as a backup server in Home or Office

U can use it as a 24/7 downloader

If the cpu is completely damaged u can use the CRT monitor as a tv by installing an ext. TV Tuner.