How to edit and save records in phpMyAdmin

[#1]

I'm pretty much a novice but I have a database set up and working that others can enter data into via the web site. However, if an entry is wrong and needs amending only I have access.
My problem is...... I go into phpMyAdmin and use the Browse option to locate the row that needs editing. I make changes to the entry and press 'Go' with the options set to 'Save' and 'Go back to previous page'. For some reason the changes are not saved.
What am I doing wrong and how should I (easily) edit records?

[#2]

PMA should provide you with information on the action taken, as a result of the SQL statement executed (it includes the SQL string run).
What does this say if anything?

[#3]

It's quite weird and baffling to me. On odd occasions the edit will be succesful and will be reported as such with the SQL code. But most of the time it reports 'no change' and there is no SQL string produced.
I'm certain that I'm being consistent with what I do each time. Sometimes it works, most times it does not.
I'm not confident enough to write the SQL code myself so I would rather use the edit function of phpMyAdmin. Any ideas ?

[#4]

Okay the only thing I can think is that you either have created an error in the sql syntax by what you have entered in the box
ie if you enter '  or " in the box without escaping them you would  normally get sql syntax errors. PHPmyAdmin doesn't actually show these errors in the normal error reporting way of php but collects these errors and shows them as an error in the sql query field.
The other thing could be if you are trying to input wrong data for the field type
ie
The field is set as an integer and your trying to enter text etc.
In both cases the DB would fail to update.