IE5 is a very old browser. Which means that cannot run some of Javascript codes to create the required cookie for your site. Try to use an up to date browser
The ?i=1 suffix is caused by a security system which relies on Javascript and Cookies to work. This should work normally with any browser and operating system from the last 15 years which hasn’t been configured in some kind of no-cookie/no-script paranoia mode.
But from what I remember of Internet Explorer, is always had some backwards security conventions, so I wouldn’t be surprised if this was caused by some misguided security system in the browser.
window 2000 and win95 along with ie5 is outdated, ie8 is the mininum version to be supported up to ie11, then there is microsoft edge in win10. Consider getting win7 + service pack 1, although it will be put onto extended support which means you can get chrome or firefox, not sure about opera.
Here is why you don’t use IE as your default browser, you only need to support IE8+, so save yourself from supporting IE7 and below.
Please (I beg you) stop using IE because it is a bad idea and microsoft agrees with that, and replaced it with microsoft edge (win 10 has it, win 7 or 8 is fine although it has IE instead (make sure you get a different browser than IE) ), then destroyed it and rebuilt it in chromium.
2nd edit: Here another reason why you don’t use IE 11 and it’s microsoft’s fault for the mess. It even forces you to turn your current javascript (ES6) into code for the previous javascript version (ES5) https://medium.com/@burger.neal/the-end-of-life-of-internet-explorer-11-12736f9ff75f