yes
One can purchase the IBM ThinkPad R51 for as little as $40 refurbished. The average price will run from around $200 to $500 depending on the specifications one is looking for.
PC-Doctor is used by Lenovo and IBM ThinkPad models.
There is no real difference. A thinkpad is just a brand of laptop computer created by IBM. There may be slight differences in design, but thinkpads run mostly the same software as any other windows laptop.
Installing DDR SDRAM on your computer will actually make your computer run faster,and will make it easier to run multiple applications at once.
Ibm? No!
Apple Macintosh software will not readily run on an IBM computer.
Yes, but some of the hardware might not be supported. There's very few programs that run on NT 3.51 anyway, It isn;t supported by Microsoft anymore, and has numerous security holes. With upgraded RAM (to at least 256 MB), the machine should run 2000 or XP quite well.
Yes
DDR RAM is the slowest type of RAM and can cause the computer to run slower
Occasionally on older motherboards, there are slots for SDRAM and DDR RAM but, they CANNOT be used at the same time, due to the different speeds they run at.
IBM compatible was a term used in the eighties to describe personal computers that could run PC-DOS the IBM operating software. These days the term is redundant.
No if you attempt this your father will spontaniously combust