Hold the fire button while the computer loads the
T800 vs T1000 sequence for invulnerability.

Or

Hex edit T2.EXE

For everlasting energy:
Search for 89 44 10 60 E8 7F
Change to: 90 90 90 60 E8 7F

For everlasting bombs:
Search for 89 45 68 60
Change to: 90 90 90 60