Is the HDD the bottleneck?

ok my mum has this HDD in he comp an i think it is slowing her comp dpwn her specs are
Intel celaron E1200 @2.5GHz
GA-73VM-S2
2x1G DDR 800MHz ram
Thermotake 430W PSU
ATI 2400 Pro
do u think this HDD id holding that comp back would it be faster if i got a WD SATA 3.0G 250G HDD to replace it

EIDE ATA/100 Only
120-GB 7200-RPM Hard Drive Specifications
General
Manufacturer Seagate
Model ST3120022A
Physical
Formatted Capacity 120 GB
Bytes Per Sector 512
Default Sectors Per Track 63
Default Read/Write Heads 16 logical / 6 physical
Default Cylinders 16 383
Dimensions Height (mm) 25.4
Width (mm) 101.6
Depth (mm) 146
Weight 635 grams
Performance
Spindle Speed (RPM) 7200
Average Latency 4.16
Track-to-Track Seek Time <1.0 (read) <1.2 (write)
Drive Ready Time 10 seconds
Average Read Seek 8.5
Buffer 2 MB
Power Requirements
Idle Mode 7.5 watts
Standby Mode 0.9 watts
Sleep Mode 0.9 watts
Environmental
Temperature Operating: 5° to 55° C
Non-operating: -40° to 70° C
Thermal Gradient (operating) 20° C (operating)
30° C (nonoperating)
Relative Humidity Operating: 5% to 90% (operating)
Non-operating: 5% to 95% (nonoperating)
Shock Operating: 63
Non-operating: 350 Gs

Yes, definitely the newer hard disk will be faster than the old and will make a difference, but it depends on what you are expecting. How do you feel the system is "slow" now?

As Know Nuttin says, a newer generation drive will be faster but some other questions need to be asked.
Does the drive seem slower now then it did before?
Is the drive partitioned, is windows on a small partition and is the drive or partition more then half full?
Does drive acess seem to freeze the cpmputer when trying to read or write files and is it specific for a particular type of action or program?

If the answer to the first question is yes and the second no, go to command prompt and type chkdsk:C /v /x /r answer yes to run at startup and type exit to exit. Reboot and allow chkdsk to run, note if it freezes at particular spots for a long time. If it does you may want to run twice. You may also get the Seatools from seagates website and run the long test.

A bad sector might be waiting to be reallocated and cannot complete without losing the sector data. It will try forever like this making drive performance seem very slow but may not complete within windows. This is a very common problem with a fairly easy fix.

i ran them tests an there was no bad sectors.