The Reason for the Prohibition Against Engaging in Work
Erev Pesach is unlike the day before other Yomim Tovim. The reason is that during the time the Beis Hamikdosh existed, from noon on Erev Pesach was the time the Korbon Pesach (Passover sacrifice) was slaughtered. The day a person would offer his sacrifice was Yom Tov for him, and he would not be permitted to do melacha (work). Since Erev Pesach was the time when all Israel offered their Korbon Pesach, therefore, certain forms of work were prohibited.
The Halacha Nowadays
Nowadays, after the destruction of the Beis Hamikdosh (Temple) we are no longer able to bring the Korbon Pesach. Nevertheless, the restriction against performing melacha was not altered. Therefore, from noon on Erev Pesach we are generally prohibited from performing any type of work which is restricted on Chol Hamoed (Intermediated days of a Yom Tov). The type of work which is permitted on Chol Hamoed is also permissible here. We are lenient to allow a non-Jew to work for a Jew on Erev Pesach.
Doing Laundry, Taking a Haircut, Cutting One’s Nails
One should finish all the laundry, take a haircut, shave and cut his nails before chatzos (Jewish halachic mid-day). If, however, he forgot to do so, he may cut his nails in the afternoon, but he may not take a haircut or shave unless it is done by a non-Jew. In case of any question, please call the rabbi.