MS DOS booted from Hard drive does not execute any .exe file even from outside

[logamuthu]

I am a 68-years old Neurosurgeon - a die-hard-fan-*censored*-avid-user(for over three decades) of MS DOS 6.22  with QBasic1.0, Foxpro for DOS 2.5

a and Wordstar 4.0 for all my work - taking at the end of every day a zipped back up of all transaction files of the day into a single 1.44

MB FDD and back them upto my other PCs via FDD / USB Pen drive / Network etc., I use Windows only for surfing - telemedicine etc.,

Recently my 10 year old mobo started acting funny - weird messages about FDD, Keyboard not present etc., After sending the old mobo to

service, I shifted the MS DOS ec., Hard disk to another mobo - removing a pre-existing XP Hard disk leaving the old MS DOS as the only HDD.

MS DOS booted fine from the old HDD and did all  internal commands like dir, type, copy etc but hung up on all .exe files - sacndisk,

qbasic, fox, foxpro, ws etc.,

I then booted from a DOS Boot Floppy and now all .exe files worked fine, except the inevitable time-lag of the processor looking up

command.com in the slower FDD each time I gave a command fom the command line or via MS DOS Batch files.

I then used sys.com in the FDD to transfer the system to the C:\ drive. Now command.com in the FDD and the C:\ on the HDD had the same size

and date stamp. Yet when I rebooted fom the hard drive - cold and hot, the .exe files did not work and the system hung!

Can anybody help Plsss!

Googol Thanx in advance!!

[Salmon Trout]

Have you still got the MS-DOS floppies? Did you do SYS C:    ? What does your CONFIG.SYS contain? what is contained in %comspec%?

see here

http://2dos.homepage.dk/batutil/help/COMM_E.HTM

[KB5cmd]

__How much RAM does your HP PC have,where I understand you installed and are running the old MS-DOS HDD?
__what is the CPU type?
__Do you have any type of lock/restriction on the HDD, as some HP PC's have set in the BIOS?
__To use old DOS programs & files you probably need to manage upper memory like Salmon Trout hinted at, with smartdrv & emm386 etc.