Hi '698523', 😄
How old is your computer? Definitely go into your Internet Options and clear out your cache and cookies, and delete your Temporary Internet Files.
Auctions all end at different times. I am not really sure what the trouble is, so maybe you could elaborate a little. When an auction is in the last hour, there is a count-down on the listing page. It is counted down second by second.
If you are looking at the bid history page, there is no countdown. There ought to be, and maybe one day, but not yet.
So if you wish to enter a last-second bid, you will need to have two windows open, and flip between the two. One where you watch the seconds tick by, and the other in which you have entered your high bid and are ready to 'confirm' at the last second.
At least that's how it works for everyone else, anyway.